I’ve flown two
different A-65 powered Fly Babies, and short-fuselage
Pietenpol Air Camper built to the original Bernie Pietenpol
plans, which was originally powered with Model A Ford and
later with a Continental O-200.
My notes here are based on the O-200 powered Pietenpol. The
Model A Ford powered Ford powered Piet is in a different class
from Fly Baby in the context of this discussion.
Control:
Roll: Fly Baby is lighter on aileron with less adverse
yaw than a Piet. The Piet’s ailerons are stiffer with a
notably slower roll rate.
Pitch: The Piet that I fly is more sensitive in pitch
than Fly Baby.
Yaw: both machines are about the same in rudder
sensitivity, however the old-school rudder bar of the Piet
gives a “mind-muscle” feel that takes some getting used to.
Power:
The Pietenpol that I fly seems happiest flying at around 70
mph. With the O-200 fitted it will go faster but the machine
get jittery and cockpit noise and wind unpleasant. Also, with
the 100 horse power there feels to be “flex” in the fuselage
at high power in climb-out.
Talking of 100 hp in a Piet, this is overpowering this ship.
From talking to other Pietenpol pilots, 65 hp is a perfectly
good fit for the airframe. I would expect a Fly Baby to cruise
about 10% faster than a Pietenpol on the same A-65, but would
expect better power and climb from the Pietenpol (flown solo
anyhow) on the same power. I think the Piet is a good choice
for alternate engines.
Handling:
The Piet glides reasonably well even with round-tube struts,
has pleasant power off handling, and tends to float a bit more
on landing that the Fly Baby. At low speeds, Fly Baby can
develop a significant sink rate.
The Piet lands at a lower speed than Fly Baby. I found the
Piet requires a lot more attention and respect in the
transition between flying and taxi speed. The Piet is more
challenging to land than a Fly Baby, but both require respect.
The low wing of the Fly Baby, along with its fixed geometry
landing gear, give it a pleasant and very predictable ground
handling. Yaw momentum is reasonably light for
both types.
Setting up brakes in a Piet equipped with a rudder bar can be
a challenge, and the Piet is lighter in the tail than a Fly
Baby thus care must be taken when applying brakes and during
engine run-ups. The Piet that I fly is more of a challenge to
land, especially on pavement. It has a split axle bungee
landing gear which has reasonably good geometry, but the
machine can be squirrelly especially in crosswind, where cross
winds can give the aeroplane a list making directional control
a challenge. In comparison, I find crosswind handling in a Fly
Baby fun! The Piet I fly feels tipper on the ground (and
downright top heavy when fitted with the water cooled Ford
engine).
Fly Baby is generally more stable, especially in rough airs.
It can be flown in anything that a general aviation light
aircraft can tackle. On the other hand, I find the Pietenpol
does not like turbulence, and can be a tiring workout in
weather that doesn’t faze a Fly Baby. I consider the Pietenpol
more of a well built, pre-historic ultralight with emphasis on
ultralight when considering operation in wind and turbulence.
Structure:
The Fly Baby is a bit more robust and more heavily-built than
a Pietenpol, but the Piet is still a good solid machine. The
Piet has many light wires and the control surfaces are rather
lightly attached compared to the Fly Baby… but proven
perfectly robust as long as they are not modified without
proper understanding (example, the rudder bar in a Piet
prevents excessive loads of the pilot’s feet from damaging
relatively delicate rudder horns and hinges). That said, I
personally don’t care for the “per plans” A-framed-on-spring
tail wheel too as I found it too flimsy.
Ergonomics and Cockpit View:
The pilot is better protected from the wind and elements in a
Fly Baby with its deeper cockpit and choice of windshields
(and canopy). There is more room for instruments and equipment
in a Fly Baby and the instrument panel is closer to the
pilot’s line of sight making it easier to monitor instruments
in critical phases of flight.
The Pietenpol that I fly is the short fuselage version (there
three versions, the longer ones apparently affording a bit
more rear cockpit room). The seat on the Piet is structural,
so more attention must be made to ergonomics during
construction. There is a bulkhead in the Piet separating the
two cockpits with penetrations cut for the pilot’s feet to
access the rudder bar. These can be opened up but some find it
restrictive.
The rudder bar, and the ergonomics of how your legs must move
to operate the rudder takes some getting used to compared to
more modern rudder pedals like in a Fly Baby. The cockpit of
the Piet feels a lot tighter than a Fly Baby and it is
definitely windier. The pilot’s increased exposure in the Piet
means that I do not fly it in cool weather while I fly my Fly
Baby in temperatures down to freezing with relative comfort.
Access to the rear cockpit of a Piet is difficult if no fillet
or access flap is fitted in the wing trailing edge. The front
cockpit in the Piet is extremely tight to get into, especially
if not fitted with the forward cabanes eliminating one of the
x-brace wires at the front cockpit. There is no door for the
front ‘pit making ingress and egress more of an adventure in
aeroplane yoga. Some folks raise the wing a few inches for
more headroom and better front cockpit access.
That said, did I mention that the Pietenpol has a front
cockpit? :)
Visibility in the 3-point is better in a Fly Baby than a
Pietenpol, and in a turn the unlimited visibility is
appreciate. The Piet on the other hand is blind as a bat in a
turn but I really appreciate the view downward when puttering
along watching the world drift by. There is room for storage
in Fly Baby, in the baggage compartment and many folks add an
extra shelf below that. The Piet has very little
storage… unless you fly solo and then you have oodles of space
to stow your gear.
Summary:
Overall, Pietenpol feels of a different era and demands
respect. The ergonomics are fair but not great as long as you
aren’t a generously large person. It is slower than most
modern aircraft and the controls aren’t overly well
balanced…but don't get me wrong, it's still FUN!
You can carry lots of stuff in the front hole, or squeeze in a
passenger. It has pleasant low speed handling and unobstructed
view downward. Looking around you and seeing all those wires,
watching the aileron cables move in union with the joystick…
keeping the ball centered while making figure eight turns and
hitting your own wake... the fresh air… the unrestricted
downward view… very retro, and very rewarding
flying.
If cockpit size and speed isn’t an issue, a conservative
alternate engine is desired, the view downward is a priority,
or you want to take a friend along for a local hop and no
desire to get anywhere in a hurry… the Piet is a great choice.
Think of it as a nostalgic 20’s retroship.
If cockpit size, comfort from wind, and cold weather flying is
important, Fly Baby is a great choice. Fly Baby is also proven
as a fair cross country ship, with pleasant handling both in
flight and on the ground, and is great for general fun-flying
yank n’ bank visibility. Fly Baby is a good, tough machine
who’s design is tolerant to modifications for aesthetic and
cockpit ergonomic reasons. Think of the Fly Baby as 1930’s
training plane.